Method and equipment for multistage liquefying of carbonaceous solid fuel

Abstract

A method for multistage transforming carbonaceous solid fuel to oil, includes mixing solid fuel ( 17 ) with heavy oil ( 40 ) to obtain fuel-oil slurry; heating and dehydrating of the slurry; liquefying of the slurry by hydrogenation under a low-medium pressure to obtain light oil ( 25 ) and heavy oil-residue slurry; hydrorefining the light oil ( 25 ) to obtain refined oil; gasifying the heavy oil-residue slurry in a gasifier ( 11 ) to obtain syngas ( 47 ); producing F-T synthesis oil ( 52 ) with the syngas ( 47 ); hydrorefining and hydrocracking the F-T synthesis oil ( 52 ) to obtain refined oil; mixing the refined oil from the F-T synthesis oil with the refined oil from liquefying by hydrogenation for producing high quality oil with low sulfur and low ammonia, and other chemical product. The method can be applied to various kinds of coals and biomass, especially applied to lignite and biomass. A suspended bed reactor for liquefying of carbonaceous solid fuel by hydrogenation is also disclosed.

What is claimed is: 
     
       1. A multistage liquefying method of carbonaceous solid fuel, wherein said method comprising the following steps:
 1) one or several kinds of carbonaceous solid fuels powder is mixed with heavy oil to make fuel-oil slurry, the fuel-oil slurry is subsequently dehydrated by heating at 150° C. to 200° C., and then partially liquefied by hydrogenation under a pressure of between 10 atm to less than 50 atm and a temperature of 350° C. to 450° C., then light oil components and a heavy oil-residue slurry are separated; 
 2) the light oil components from the step 1) are hydrorefined to yield refined oil; 
 3) the heavy oil-residue slurry from the step 1) is introduced into an oil-residue-slurry pressurized gasifier at a temperature of 100° C. to 400° C. to perform the gasification reaction with oxygen at a temperature of 1000° C. to 1800° C. to yield syngas, wherein the heating value of said heavy oil-residue slurry is in a range of 6000 kcal/kg to 9000 kcal/kg; 
 4) the syngas from the step 3) is treated by conventional process and then converted to F-T synthesis oil using conventional F-T synthesis process; and 
 5) the F-T synthesis oil from the step 4) is then hydrorefined and hydrocracked to produce refined oil, which is combined with the refined oil from the step 2), and then fractionated to yield high quality oil products including LPG, gasoline, aviation kerosene, diesel oil or other chemical products. 
 
     
     
       2. The method according to  claim 1 , wherein said carbonaceous solid fuels include a variety of high quality coals and low-rank coals, and different kinds of carbonaceous biomass. 
     
     
       3. The method according to  claim 2 , wherein said low-rank coal preferably is lignite. 
     
     
       4. The method according to  claim 1 , wherein said heavy oil for making said fuel-oil slurry in the step 1) is the heavy oil separated from said heavy oil-residue slurry, a product of said hydrogenation of the step 1); said heavy oil is directly used as a feedstock for preparing fuel-oil slurry, or partially or completely hydrogenated before preparing said fuel-oil slurry. 
     
     
       5. The method according to  claim 1 , wherein the solid content of said fuel-oil slurry of the step 1) is from 10 wt % to 70 wt %, based on the total weight of said fuel-oil slurry. 
     
     
       6. The method according to  claim 1 , wherein a residence time of said liquefaction by hydrogenation of said fuel-oil slurry in the step 1) ranges from 20 minutes to 1.5 hours; a yield of light oil components of said method accounts for 5 wt % to 40 wt %, based on the total weight of said solid fuel. 
     
     
       7. The method according to  claim 1 , wherein a spent catalyst of said F-T synthesis process is used for liquefaction by hydrogenation of said fuel-oil slurry in the step 1). 
     
     
       8. The method according to  claim 1 , wherein the slurry of said heavy oil-residue slurry from the step 1) is spray-cooled into solid powder, then made into coal water slurry for producing syngas by gasification or as boiler fuel for producing power steam. 
     
     
       9. The method according to  claim 1 , wherein said oil products obtained by the method contains less than 6 ppm of sulphur and less than 10 ppm of nitrogen; preferably, a octane number of said gasoline obtained by the method is between 90 and 98; a specific gravity of said aviation kerosene ranges from 0.74 to 0.83, and a cold filter plugging point ranges from −66° C. to −49° C.; or a cetane number of said diesel oil is from 55 to 70, and the cold filter plugging point is from −45° C. to 0° C. 
     
     
       10. The method according to  claim 1 , wherein the solid content of said fuel-oil slurry of the step 1) is from 20 wt % to 65 wt %, based on the total weight of said fuel-oil slurry. 
     
     
       11. The method according to  claim 1 , wherein the solid content of said fuel-oil slurry of the step 1) is from 40 wt % to 65 wt %, based on the total weight of said fuel-oil slurry. 
     
     
       12. The method according to  claim 1 , wherein a residence time of said liquefaction by hydrogenation of said fuel-oil slurry in the step 1) ranges from 20 minutes to 1 hour; a yield of light oil components of said method accounts for 5 wt % to 25 wt %, based on the total weight of said solid fuel.